In modern circumstances, it is difficult and expensive to train soldiers and military defense personnel in the effective use of high-powered rapid-fire machine guns, by simply allowing such individuals to practice using the actual guns with live ammunition. The ammunition rounds are expensive, for example costing up to five dollars per round. The cost of ammunition alone quickly multiplies when it is recognized that a typical machine gun is capable of firing hundreds of rounds per minute. Adequate space for a practice gunnery range may not be readily available. Increased cost is involved in transporting the personnel and the equipment to suitable remote locations where adequate gunnery practice can be performed. Safety is always a major consideration when live ammunition rounds are fired, both to military personnel involved in gunnery practice and to non-military personnel who may be adjacent to the gunnery range. It is difficult to instruct during a live ammunition training session due to the noise and safety considerations involved when others are involved in similar, close-by, live-ammunition practice activities. Furthermore, it may be difficult to vary the targets quickly at a live-ammunition gunnery range.
These problems and practical constraints are exacerbated when training individuals to shoot from a moving vehicle such as a helicopter. If live ammunition practice is attempted from a moving helicopter, a large space is required in order to maneuver the helicopter and to provide targets and adequate safety barriers, especially when multiple individuals are involved in similar simultaneous training exercises. As a result, live gun practice requires considerable space, and the cost of operating the helicopter greatly multiplies the overall training cost.
Because of these and other considerations, simulated weapon training programs have been developed for teaching purposes. Such training programs use imitation machine guns which closely simulate the sensational aspects and the mechanical and physical requirements of firing actual machine guns. Firing is simulated by reproducing effects which mirror the sensual perceptions associated with firing the actual machine gun. The environment and the targets are electronically displayed, allowing them to be more easily varied and to simulate movement of the targets and the machine gun. The trajectory of the simulated bullet fired is also calculated. In those cases where the simulated fired bullet emulates a tracer, the trajectory of that simulated bullet is also displayed in the surrounding environment.
For helicopter gun training, the imitation machine gun is mounted in an open door of an imitation portion of the helicopter fuselage. The environment and the targets are displayed outside of the open door. The portion of the imitation helicopter fuselage is moved or shaken in a manner similar to the movement of an actual helicopter in flight while the display of the surrounding environment and the targets are moved to simulate the flight path of the helicopter.
Simulated weapons training programs offer other benefits. Environments of remote areas of the world may be simulated, thereby providing training exposure to such environments prior to actually deploying the military personnel to those locales. The accuracy of the training program and the abilities of the individuals trained may be assessed. The accuracy in shooting, and the success of the training itself, is gauged by comparing the calculated, projected trajectory of the simulated bullets relative to the displayed targets. The number of simulated rounds fired may also be counted to evaluate the efficiency of the individual doing the shooting. Other factors can be evaluated from the vast amount of information available from such computer-based simulated weapons training programs.
Of course, to be effective for training purposes, it is necessary to create a realistic simulated environment and a realistic experience of firing the imitation machine gun. Such simulation is accomplished principally by multiple computer systems which are programmed to perform their specific simulation activities in coordination with each other. In the end, the capability of the simulated weapons training program to imitate the actual use of the actual machine gun in an actual environment is the ultimate measure of effective and successful training.
Accurately simulating the firing of an actual machine gun involves duplicating the recoil or reactive impact created by firing each ammunition round. A momentary rearward impact occurs in reaction to the forward acceleration of the bullet moving out of the barrel and in reaction to a reciprocating movement of an internal bolt of the gun. The explosive force from firing the round drives the bolt rearward against the force of a bolt actuating spring. The rearward movement of the bolt automatically ejects the spent casing, withdraws the next live round from the ammunition belt, expels a connection link which joined the withdrawn round to the next round of the ammunition belt, positions the withdrawn round on the bolt for loading and firing, and advances the ammunition belt to locate the next round to undergo similar actions after active round has been fired. Depressing the trigger enables the compressed bolt actuating spring to drive the bolt forward to load the round into a firing chamber and then fire that loaded round. The pressure from the exploded round drives the bolt rearwardly against the compression force of the bolt actuating spring. The sequence of events continues in the same manner with each subsequent pull of the trigger, or the sequence of events continues repetitively and continuously while the trigger remains depressed. The individual operating the gun feels the sensation of this reaction as recoil of the machine gun.
Larger and higher power ammunition rounds create greater reactive recoil. Since the capability to load and fire each ammunition round is set or adjusted by the force of the bolt actuating spring and other physical components of the actual machine gun, the frequency and strength of the sequential recoil impacts may vary according to the type of ammunition and the spring characteristics of the bolt activating spring.
In a imitation machine gun, the repetitive recoil impacts of firing ammunition rounds are simulated by a recoil simulation device. The recoil simulation device generates the reactive impact that simulates the recoil impact of firing a live ammunition round and reciprocating the bolt in an actual machine gun. One previous imitation machine gun reciprocates an internal bolt when firing a simulated round, to contribute to generating the recoil effect.
The imitation machine gun should emulate the functionality of the actual machine gun to the greatest extent possible. Individuals become accustomed to the imitation machine gun due to the amount of simulated training received. Because of the familiarity gained from training with the imitation machine gun, use of the imitation machine gun should be essentially the same as the use of the actual machine gun; otherwise, differences in functionality or performance create unexpected problems or difficulties when using the actual machine gun.
Accurately simulating the effect of using an actual machine gun means that using the imitation machine gun should not require additional actions which are not involved in using the actual machine gun. Extra external parts, such as hoses which carry hydraulic or pneumatic fluid for operating some feature of the imitation machine gun, cause a lack of familiarity or awkwardness when it comes to using the actual machine gun. Extra external parts may also create an expectation of a certain feel, appearance and operating style that are not present when using the actual machine gun. Known prior art recoil simulator mechanisms suffer from the disadvantages of requiring extra external parts and requiring extra actions not involved in using an actual machine gun. Known prior art recoil mechanisms also create sensations which are not faithful reproductions of the sensations created when using the actual machine gun. These extra external parts, actions and sensations lead to a potential for degraded performance when using the actual machine gun.